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Biomedical subjects

W Meyer

Publications and source records attributed to W Meyer.

At least 109 records · Page 6Linked to original sources
PubMed1998

Melatonin supplementation does not prevent photostimulatory effects of night interruption lighting in Japanese quail.

Male Japanese quail (Coturnix japonica) exposed to night interruption lighting were given melatonin either as single daily injections (10-100 mg/kg), or as continuous release implants. Birds were exposed to a base photoperiod of 8 hr of light, plus a 15 min night interruption pulse of light 14 hr after the beginning of the base photoperiod. Daily injections of melatonin were given 20 min prior to the night interruption pulse. Control birds either received no exogenous melatonin or received injections during the last 2 min of the night interruption pulse. Exogenous melatonin was able to induce sleep-like behavior at higher doses but did not prevent gonadal recrudescence as measured by the cloacal protrusion area. The role of melatonin in avian reproduction appears to be different from that in mammals. Perhaps melatonin's role in birds is to regulate circadian activities, not circannual ones such as the onset of reproduction.

Animals↗
PubMed1998

De-frauded?

Explore the source record for details and available documents.

Fraud↗
PubMed1998

Ultrasonically dense amniotic fluid in early pregnancy in asymptomatic women without vaginal bleeding. A report of two cases.

BACKGROUND: During the second trimester of pregnancy, the presence of free-floating particles in the amniotic fluid on ultrasonography has been associated with aggregates of cells or fetal blood and with unexplained elevation of maternal serum alpha-fetoprotein and the later development of abruptio placentae and fetal distress. During the third trimester, particulate amniotic fluid is thought to represent meconium or vernix. CASES: An unusual, ultrasonically dense appearance of the amniotic fluid was noted prior to 18 weeks of pregnancy in two asymptomatic women who carried exencephalic fetuses. In both cases, prenatal evaluation of the amniotic fluid suggested that the free-floating particles were due to the presence of blood. CONCLUSION: A detailed ultrasonographic evaluation should be undertaken should dense amniotic fluid be detected early in pregnancy because this sign may help in the early diagnosis of fetuses with congenital malformations likely to bleed.

Adult↗
PubMed1998

[History of the Turkish angora goat with remarks on the wild ancestor of the domestic coat].

The study describes the ancient (3000 B.C.-15th/16th Century A.D.) and the more recent (16th-20th Century A.D.) history of the Turkish Angora goat as based on a broad and intensive evaluation of relevant literature. Moreover, important structural features of the typical biotope of this caprine breed are explained, essential basic information from a comparative zoological point of view is added with regard to the development of goat domestication, and specific details relating to the history of civilization are supplied. For a better understanding of all the different topics dealt with, selected and mostly original illustrations are included.

Animal Husbandry↗
PubMed1998

Remote quantitation server for quality assurance in DNA ploidy analysis.

OBJECTIVE: To remotely test a stepwise framework of quality control measures, developed according to the 1997 European Society of Analytical Cellular Pathology consensus on diagnostic DNA image cytometry, in two series of measurements by means of the quantitation server EUROQUANT. STUDY DESIGN: In each of these series, 104 fine needle aspiration biopsies, imprints from breast cancer specimens and 28 rat liver imprints were measured twice at two different cytometry workstations. Further measurements on special rat liver specimens for evaluation of the stability of the machinery and of the preparation process were done at both workstations. Afterwards the measurement data from both machines were transferred to the quantitation server and analyzed automatically. Beside the classical DNA histograms, a set of further evaluations was performed to detect optical errors as well as inhomogeneities in the measurements. Running values for mean integrated optical density values, mean corrective factors and mean coefficients of variations of corrective factors were computed to control the stability of the entire methodology over time. RESULTS: The study demonstrated the preconditions and outcome of server-based quality control in DNA ploidy analysis. The results show that such a remote analysis is feasible and comparable to local DNA ploidy analysis. It is also demonstrated how quality control tests reflect the process performance of ploidy analysis at its different levels. CONCLUSION: Quality control must be an inherent part of the daily routine to allow a reliable diagnostic interpretation and ensure steadily high product quality.

Animals↗
PubMed1997

Transvaginal ultrasonographic (TVS) evaluation of baboon gestation from 37-62 days postconception.

Our objective was to determine the growth of the embryo and surrounding structures during baboon (Papio anubis) gestation using transvaginal sonography (TVS). To this end, we evaluated 19 timed-mated baboons using TVS between 37 and 62 days of gestation. After visualization of the gestational sac, amniotic sac, and yolk sac, the three largest diameters of each of these extra embryonic structures were measured using longitudinal and transverse views. Embryonic crown-rump length (CRL) was also recorded. Embryonic heart rates were determined using the M-mode function of the ultrasound equipment. All 19 gestations developed without complications. No significant trend could be demonstrated for heart rate or yolk sac diameters over the 37-62 day gestational age period. Mean (SD) gestational age in days, heart rate, and yolk sac diameter, respectively, for the group were 48 (7.8) days (range: 37-61), 180 (15) beats per minute (range: 156-221) and 5 (0.1) mm (range: 3-8). Significant correlations (P < 0.0001) were determined between gestational age and CRL and gestational and amniotic sacs. We conclude that TVS allows a clear visualization of the embryo proper and all the cavities within the gestational sac of the baboon gestation. This study has determined the normal pattern of changes of these cavities from 37-62 days of gestation. Future applications of these findings may include sampling fluid from these cavities for biochemical, cytological, and metabolic studies.

Animals↗
PubMed1997

Identification of pathogenic yeasts of the imperfect genus Candida by polymerase chain reaction fingerprinting.

With the increase in the number of immunocompromised hosts, the number of fungal pathogens has increased markedly. Identification and classification, especially of yeast species and strains, is often difficult when based solely on phenotypic characteristics. Since it became clear that different fungal pathogens require specific treatment strategies, there is a need for simple, rapid and reliable methods to identify fungal isolates. Polymerase chain reaction (PCR) fingerprinting was successfully applied here to identify yeast isolates. Microsatellite [(GTG)5; (GACA)4] and minisatellite [(5'GAGGGTGGCGGTTCT 3'), derived from the core-sequence of the phage M13] specific primers were used as single primers in the PCR to amplify hypervariable interrepeat DNA sequences from over 200 European, American and Australian clinical isolates within the genus Candida. Each species, represented by its type strain, could be identified by a specific multilocus pattern, allowing for the assignment of all the isolates to the appropriate species. Intra-species variation in the multilocus profiles was about 20% compared to inter-species variation, which was up to 80%. Anamorph-teleomorph pairs could be identified by highly homologous PCR fingerprint patterns. PCR fingerprinting was more discriminatory when compared with routinely used biochemical tests (Vitek YBC and API ID 32C). PCR fingerprinting has proven to be a powerful tool for the identification of medically important yeasts. It is rapid, sensitive, reliable, highly reproducible, stable in vitro and in vivo, and applicable to large scale experiments. Potential applications include: yeast taxonomy, epidemiology, environmental surveys, and improvement of the diagnosis of mycotic diseases.

Australia↗
PubMed1997

A mutation in cytochrome oxidase subunit 2 restores respiration of the mutant pet ts1402.

The yeast PET1402/OXA1 gene encoding a 44.8-kDa protein is required for mitochondrial biogenesis. Substitution of Leu240 to serine in the protein results in an accumulation of the precursor form of the mitochondrially encoded subunit 2 of cytochrome oxidase (Cox2) and temperature-sensitive respiration. This temperature sensitivity can be suppressed by a mutation in the cox2 gene changing Ala189 of the Cox2 protein to proline. In the cox2-ts1402 double mutant respiration is restored without removal of the Cox2 pre-sequence. The suppression suggests an interaction of the Pet1402 protein with the cytochrome oxidase complex. Antibodies raised against the predicted C-terminus and the tagged N-terminus of the Pet1402 protein reacted with a 37-kDa polypeptide. This protein, present in the mitochondrial fraction, is localized within the inner membrane. The difference in size can be explained by the removal of the predicted mitochondrial-targeting sequence from the Pet1402 protein. The mitochondrial localization of the protein points to a direct interaction with the cytochrome oxidase complex.

Amino Acid Sequence↗
PubMed1997

Applying what burn survivors have to say to future therapeutic interventions.

Statements by caregivers can be beneficial to paediatric burn patients, facilitating their psychological adaptation. However, the concerns of the burned child are not always obvious, and caregivers may flounder, not knowing how to elicit the concerns of the patient. The purpose of this paper is to examine whether universal concerns of the postburn survivor can be detected through one type of psychological assessment tool, a sentence completion task. Sixty paediatric burn survivors, ages 6-19, were administered a 30-item Incomplete Sentences measure. Five major aspects of postburn life were identified and proscribed the following descriptive labels: (1) preoccupation with health; (2) the struggle for internal acceptance; (3) reconstruction of one's life map; (4) changing relationships; and (5) redefining the world. These five dimensions of postburn life are discussed, as well as applications for each.

Adaptation, Psychological↗
PubMed1997

An automated radiopharmaceutical dispenser.

An automated radiopharmaceutical dispenser, that offers several advantages over manual procedures, has been developed. It employs a personal computer interfaced to a precision syringe drive module, a dose calibrator, and a printer. The operating program provides menu-selection operation and documentation of procedures and individual doses delivered. All materials in contact with the radiopharmaceutical are sterile and disposable. A novel transport safe is employed to further reduce radiation exposure.

Deoxyglucose↗
PubMed1997

[CT angiography of cerebral venous circulation: anatomical visualization and diagnostic pitfalls in interpretation].

PURPOSE: To show the frequency of visualisation of the dural sinuses and cerebral veins with CT-angiography (CTA) with special reference to anatomical variants. METHODS: 34 CTA (1 mm slice thickness, 120 ml nonionic KM, 2 ml/s flow, 40 s prescanning delay) were performed in 30 patients to examine the cerebral venous system. In an anatomic study of cadavers (n = 10) without known disease of the cerebral veins the great sinuses were opened and examined. RESULTS: The superior sagittal, the transverse, the sigmoid and the straight sinus could be evaluated in all cases (100%). The cortical and deep cerebral veins as well as the small sinuses were visualised in 12-97% of the examinations. A sinovenous thrombosis was diagnosed in 4 of the 30 patients. Asymmetric superior sagittal sinus bifurcation (12/30), a hypoplastic sinus transversus (2/30) and a persistent sinus occipitalis (4/30) were found as anatomical variants. In 10 of the 30 patients we discovered 17 dural sinus filling defects produced by large arachnoid granulations. Similar findings could be demonstrated in the pathologico-anatomic examination series. CONCLUSION: CT angiography is suitable for detailed evaluation of the cerebral veins. Anatomic variants, arachnoid granulations, as well as fibrous bands and septa, which may lead to misinterpretation in conventional CT, can be clearly demonstrated. The sensitivity and specificity of CT in diagnosis of sinovenous thrombosis were increased thereby.

Adolescent↗
PubMed1997

Irinotecan hydrochloride (CPT-11) resistance identified by K-ras mutation in patients with progressive colon cancer after treatment with 5-fluorouracil (5-FU).

OBJECTIVE: To determine the prognostic role of a K-ras mutation in tumor tissue of patients with refractory colon cancer who received irinotecan hydrochloride (CPT-11). METHODS: DNA was extracted from paraffin-stored tumor tissue of 35 patients with progressive colon cancer failing treatment with 5-fluorouracil who subsequently received CPT-11 (100 mg/m2 i.v. per week x 4 weeks with 2 weeks off per course). The first exon of the K-ras gene was amplified by polymerase chain reaction by using K-ras-specific primers followed by mutant enrichment sequencing. Survival differences of patients with a K-ras mutation were compared with those of patients with a normal K-ras status. RESULTS: A total of 21 patients had a normal K-ras sequence and 14 patients had a K-ras mutation [GAT, n = 7; TGT, n = 3; and GCT, AGT, GTT, GAC (codon 13), n = 1 each]. Median survival of patients with a normal ras sequence from time of treatment with CPT-11 was 332 days compared with 169 days for patients with a K-ras mutation (p = 0.0036). No differences in age, sex, cancer stage, surgical treatment, or chemotherapy treatment were observed. CONCLUSION: Determination of the presence of a K-ras mutation may predict survival in patients with progressive colon cancer after treatment with 5-fluorouracil who receive CPT-11.

Adenine↗
PubMed1997

Comparison of use of phenotypic and genotypic characteristics for identification of species of the anamorph genus Candida and related teleomorph yeast species.

A total of 49 type and neotype isolates and 32 clinical isolates of the anamorph genus Candida and related teleomorph genera were obtained from different culture collections and clinical laboratories. Isolates were subjected to two phenotypic methods of identification, Vitek yeast biochemical card (YBC) and API ID 32C, both based on carbohydrate assimilation, and one genotypic method, PCR fingerprinting, based on the detection of DNA polymorphisms between minisatellite-specific sequences with the primer M13 (5' GAGGGTGGCGGTTCT 3'). The correct identification of a strain at the Centraalbureau voor Schimmelcultures was used as the gold standard for the identification of an isolate. When the study was restricted to species included in the respective biochemical databases, the Vitek YBC and API ID 32C systems performed adequately with positive identification rates of 87.3 and 76.8%, respectively. When uncommon species were added to the study, several of which are not included in the databases, the identification efficiencies were 76.5 and 77.5%, respectively. By comparison, all isolates were correctly identified by PCR fingerprinting, with 63 reference species profiles in the databank. Sufficient polymorphisms among the total set of banding patterns were observed, with adequate similarity in the major patterns obtained from a given species, to allow each isolate to be assigned unambiguously to a particular species. In addition, variations in minor bands allowed for differentiation to the strain level. PCR fingerprinting was found to be rapid, reproducible, and more cost-effective than either biochemical approach. Our results provide reference laboratories with an improved identification method for yeasts based on genotypic rather than phenotypic markers.

Base Sequence↗
PubMed1997

Stabilities of free and complexed human immunodeficiency virus p24 antigens during short- and long-term storage.

By the standard p24 assay there was a 25 to 27% decrease in free p24 antigen in serum after storage at 4 degrees C over 14 days but no loss at -70 degrees C. There was no loss at either temperature by the immune complex dissociation (ICD) procedure. Furthermore, there was no significant loss of detectable p24 in serum by either the ICD or the standard p24 assay after 700 days of storage at -70 degrees C.

Antigen-Antibody Complex↗